buildPath

Adds the path element of an item id to the path currently being built.
Recursively invoked method that may be overridden by some subclass to
either return cached responses or add response to cache. On exit,
builder contains the path of state.

Overridden method tries to find a mapping for the intermediate item
state and add its path elements to the builder currently
being used. If no mapping is found, the item is cached instead after
the base implementation has been invoked.

nodeModified

Called when a node has been modified, typically as a result of removal
or addition of a child node.

Please note, that this method is not called if
ItemStateListener.stateModified(ItemState) was called.
If path information is cached for modified, this iterates
over all child nodes in the path map, evicting the ones that do not
(longer) exist in the underlying NodeState.